Furnace.



PATENTED 001". 17, 1905. W. L. .FORSTER. FURNACE.

APPLICATION FILED FEB. 8, 1904.

5 MM by "UNITED STATES PATENT WILLIAM L. FORSTER, OF CHICAGO, ILLINOIS,ASSIGNOR TO PROTECTED FURNACE PORT CO., OF CHICAGO, ILLINOIS, ACORPORATION OF ILLINOIS.

FURNACE.

Specification of Letters Patent.

Patented Oct. 17, 1905.

Application filed F ruary 8, 1904. Serial No. 192,655.

To ctZZ whom it may c0ncern:

' Be it known that I, WILLIAM L. FoRs'rER, a citizen of the UnitedStates of America, residing at Chicago, in the county of Cook and Stateof Illinois, have invented certain new and useful Improvements inFurnaces,of which the following is a specification.

My invention relates to certain new and useful improvements in furnaces;and its object is to produce a device of this class which shall havecertain advantages which will appear more fully and at large in thecourse of this specification.

To this end my invention consists in certain novelgfeatures ofconstruction, which are clearly illustrated in the accompanying draw-,ings and described in the specification.

In the aforesaid drawings, Figure l is a longitudinal section through anopen-hearth furnace embodying my construction, the section at theleft-hand end of Fig. 1 being in the line 1 l of Fig. 3 and the sectionat the right-hand end thereof being in the line 1 1 of Fig. 3. Fig. 2 isa section in the line 2 2 of Fig. 1, and Fig. 3 is a section in the line3 3 of Fig. 1 looking in the direction of the arrow.

The furnace herein illustrated is of the type known as open hearth, andit is for this type of furnace that my invention is particularlydesigned; but it could be used with the so-called heating-furnace, theobject of which is to heat iron and steel ingots preparatory to forgingrather than to produce steel, as is done with the furnace hereinillustrated. In both these types of furnace the two ends aresubstantially duplicates, each having an air-inlet and a gas-inlet, andin practice the air and gas are let in at one end for a certain periodof time, burning in the body of the furnace and passing out through theair and gas inlets at the other end of the furnace, the burning andburned vapor being passed through suitable valves to chambers commonlycalled regenerators, which they heat to a high temperature beforepassing up the stack. After the furnace has been used for a certainperiod with the vapor passing in one direction the gas and air are shutoff at one end and admitted at the other, passing through theregenerators and being intensely heated before being introduced into thefurnace. It is owing to the fact that these regenerators are heated bythe exhaust-vapor and are cooled down by the incoming vapor that it isnecessary to reverse the action of the furnace from time to time, thereversals taking place in ordinary operations at intervals of aboutfifteen minutes. It will be seen that the ports of the furnace servealternately the purpose of inlet-ports for the unburned gas and air andfor the burned and burning vapor in an intensely-heated condition.

In describing the construction of this furnace one end only will beparticularly described, it being understood that the two ends areconstructed substantially alike.

Referring now to the drawings, A is the body of the furnace, in which isplaced a quantity of the material to be acted upon, in the case of anordinary open-hearth furnace this material being iron and suitablecarbon-furnishing material for the production of 'steel.

B indicates an arch which opens into one end of the furnace, this archbeing inclined downwardly, so that vapor passing down it will bedeflected into the lower part of the furnace. At the rear end of thisarch is a rear wall C. In front of this wall are twolongitudinally-extending walls 0, Fig. 3, which olivide the spaceimmediately inside the rear wall into three fines 0 c 0 the fines 0being at the two sides of the flue 0 The two walls 0 are surmounted attheir top by an inner arch 0 which covers the top of the center flue cThis arch lies within the outer arch B and has I its upper surfacesubstantially parallel therewith. It will also be seen that the two sidefines c 0 communicate with the space above this arch, so that vaporpassing up the side flues will pass out under the arch B above the innerarch 0 while vapor passing up the center flue will pass underneath thisarch, and the two streams of vapor will mix immediately beyond theforward edge of this inner arch. Immediately below the forward edge ofthe inner arch c" is situated a hollow wedge-shaped metallic shield D,adapted to receive and hold a body of water. This shield, it will benoted, has its upper surface in con tinuous contact with the fiat lowersurface of the inner arch 0 said upper surface of the shield beingadapted to form a support for the arch, as will be hereinafter setforth. A plurality of pipes D run through the walls of the furnace andenter one side of this shield, the opposite ends of the pipes D beingconnected by suitable pipes D, having valves (Z,

with a supply-pipe D Similar pipes D lead from the opposite side of theshield 1D and are connected to outlet-pipes CZ, having valves 6Z2. Belowthe ends of these outlet-pipes is a suit able trough or basin 1),connected to a suitable sewer pipe or the like. It is to be noted thatthe larger end of the wedge-shaped shield is situated at the point ofthe arch, so that the bottom surface of this shield has a slantingsurface sloping toward the center of the furnace.

In operating my improved furnace the gas passes up through the centerflue and out under the inner arch 0 and the air passes up the side fluesand out above the arch. Both gas and air are very highly heated frompass- 1ng through the regenerators, as above described, and owing to theintense heat of the furnace and their own heated condition they mix andignite spontaneously immediately after passing the outer edge of theinner arch 0 and in their burning condition they pass down through thespace under the outer arch B into the lower part of the furnace-body.The vapor then passes out under the corresponding arch at the other endof the furnace, impinges against the edge of the inner arch at that endof the furnace,,and is divided into two parts, one of which passes outthrough the air-flue and the other through the gas-flue at the other endof the furnace. It will be seen, then, that the entire mass of heatedvapor immediately after passing through the furnace strikes against theedge of the inner arch, and this point is therefore the most vulnerableof the entire furnace. Furthermore, it is absolu tel y essential to theproper action of the furnace that the edge of this arch be maintained atexactly the right position, for the reason that if it is allowed to meltoff the gas and air will mix too far up the space under the arch B andwill be improperly ignited. Owing to the agitation of the vapor arisingfrom improper ignition, the directing force of the blast will to a largeextent be lost, and the vapor instead of being-directed down into thebottom of the furnace will rise and strike the top of the furnace justoutside the end of the arch B and owing to its intense heat will attackthe furnace at that point,causing it to rapidly go to pieces. To protectthis particularly vulnerable point of the furnace, cold water is flowedcontinuously through the shield immediately under its most exposed edge.The shield cools the vapor immediately in contact .with the arch to acertain extent, and it also serves as a shelf which supports anyloosened portions of the arch. The peculiar advantage which arises fromthis wedge -shaped shield lies in the fact that the water within theshield tends to flow by gravity into the end of the shield nearest thecenter of the furnace. Thus steam is prevented from accumulating in thatend of the shield which is most exposed to the heat and forcing away thewater from this exposed part. With a shield having a flat lower surfacesome difficulty might arise through the accumulation of steam at the hotend of the pipe, and this peculiar construction is adapted to preventthis accumulation.

I realize that considerable variation is possible in the details of thisconstruction withoutdeparting from the spirit of the invention, and Itherefore do not intend to limit myself to the specific form hereinshown and described.

I claim as new and desire to secure by Letters Patent- In a device ofthe class described, the combination with the body of a furnace and anouter arch at each end of the same, of an inner arch within each of saidouter arches, and out of contact therewith, passages for conducting gasto one side of said inner arch and air to the opposite'side thereof, ahollow watershield below said inner arch having a fiat lower surfaceinclined downward toward the exposed face of the arch, and means forconducting water to and from said shield.

In witness whereof'I have signed the above application for LettersPatent, at Chicago, in the county of Cook and State of Illinois, this 3dday of February, A. D. 1904.

WILLIAM L. roRsTER.

Witnesses:

LOUISA S. FRENCH, SAMUEL A. FRENCH.

